Process of recovering sodium and potassium salts from mixtures thereof.



- No Drawing.

. nardino county, California.

ent salts of this liquor are: sodium chlorid, about 1/2, sodium sulfate, about 1/6, sodium UNITED sTA EsfPArENT OFFICE j CLINTON E. DOLBEAR, or BERKELEY, oAnIFo NIA, ASS

' or-nnaxnnnr, CALIFORNIA.

all whom it may concern: Be it known that I, CLIN'roN E..DQLBEAR, a citizen of the United States, residing at Berkeley, in the county ofv Alameda and State of California, have invented new and useful-Improvements 1n Processes offltea covering Sodium andPotassiuiI-i Salts from Mixtures Thereof, of Which the following is a specification.

'The present invention relates to a. method of separately recovering the more valuable constituents of a saline liquor such as is found in Searles Borax Lake in 'SanBer- The -constitucarbonate; about .1/7, potassiumchlorid,

about 1/7, sodium biborate about 1/21.

The object of the invention is to provide a process by which the valuable constituents of said liquor -may be recoveredat a cost commercial sufliciently low to permit ofl-its use.

The following are the steps of my,'i1nproved process :.The solution is subjected Na,SO, are crystallized out, until" the solution becomes saturated with some one or more of the other contained salts, and at that point to alowe'ring of'the temperature to notbelow 18 C;=Whereby are crystallized out portions of the salts other than NaCl and Na 'SO The lower-temperature should not be below 18 C., below which Na,SO,LlOH O would re-form and precipitate. At the above temperatures,

. The salts crystallized out on lowering of the temperature consists of Na CO Na B O and KGl'. These are then separated from the mother liquor in'any known or suitable way, and aresubs'equent'ly redissolved in. water to saturation and'thensubjected to further treatment as follows-:-

The Na CO is precipitated as NaH'CO, "by

passing '00, through the solution. The solution is then treated with a more or' less soluble compound. of an alkaline earth metal such as Ca(OH) or CaCl whereby the; Na IiO, is converted into (la-13,0 and I QNaOI'Lor' QNaCl, as the case may be! The 62113 0 is insoluble andprecipitates out.

The KCl is then recovered by ordinary" 0., whereby NaCl.

the l la ,S-O. isprecipitated -With the NaOl.

common to the two processes rnoonss or REoovnit NG. somuivr A nro'rAssIuM SAL T s FROM M i'rUREs THEREOF.

1 Specification of Letters Patent. i Patented Feb 24 1914; Appli'cationfiled April 1o; 191-2'.- Serial No. ssas'zs.

evaporation." The residual solution,- remaining at theendof the first-named step of IG on To SELIJAY'H H. MERRILL,

evaporating at a higher -teinperature and thenlowering the-temperature is added to a fresh supply of the'original'fsolution and the process is continued indefinitely. After each precipitation, the residual solution and the precipitate wouldnaturally be separated from each other. The separation can be effected in any, knownbr, suitable Way.

sodium sulfate from the liquor by fractional crystallization, I am enabled to. obtain a crude mixture of saltswhich can be shipped at a low rate to-a point. where theyacan be under other favorable conditions.

' The mixture of sodium sulfate and sodiuin chlorid can'be disposed of as may be de' ,sired. Unless the market price of these salts should exceed [the costof' getting them to-market (incliidingthe cost of separatingv them, if required fprmarketing) it would be best to leavef'thern in the vicinity :of the place of original production. The ability to do this-arid thus tov avoid expense for transporting such low priced substances to a place where the remaining steps of. the process can best be formed is an advantage ofthe present method.

In an application" which I filed of even numbered 689,877 I have described a process V .70 refined at a low cost of labor and fuel, and

date herewithand Which-has been ol'licially for separately recovering saline substances '1 from the aforesaid liquor of Searles Borax Lake which consistsin (-1)' passing carbon.

' dioxid through saidliquor in order to precipitate sodium bicarbonate, (2) treating the residual solution with a moreor less .soluble compound of an alkaline earth metal, such as calcium hydroxid or calcium chlorid in order to obtain the boric acid of the sodium .biborate in an insoluble form, (3) subjecting the residual solution to evaporation at a temperature greater than 33 .C'.

until saturated With potassium chlorid in order to crystallize sodium chlorid and 1 sodium sulfate out of the solution, and (4:)

lowering thetem-perature to not below 18 C. in order to crystallizepotassium chlorid out of the solution.

- Those features- (to wit, all and singular the new, useful, and original :parts, improvements and combinations) which are are intended to a es' By first eliminatingsod'lum chlorid and be claimed in my said application of-even I date 0. 689,877...Those-:Eeatures inywhich the processes differ. from each-i other are "sodium carbonate,

slum chlorld, sod um sulfate and 'SOdIHIII,

severally tions." I I claim:: T i l. j. The method of, separately recovering saline substances from asolution Containing sodium biborate, potasclaimed in therespective applicachlorid which consists in, first, separating sodium I chlorid and sodium sulfate jfrom .other' salts by subjecting the'solution to evaporationvat atemperature greater than 83 C. and to a lowering of the temperature tonotbelow 189 C. redissolving the precipitated sodiumcarbonate, sodium biborate and potassium ohlorid, passing throughthe solution carbon dioxid to'form and precipitate sodium bicarbonate; then mixing the solutio-nwith ainore or less soluble compound "of an alkaline earth metal 'to precipitate therefrointhe corresponding biborate, and then recovering the potassium chlorid by ordinary' evaporation.

. 2. The method ofseparately recovering saline substances-froma solution containing sodium .carb0-nate, sodium biborate, potassium chlorid, and sodium chlorid which consists in, first, separating sodium chlorid from othersalts by subjecting the solution to evaporation at-a higher temperature and a to a lowering of the temperature, redissolv ing the precipitated sodium ;carbonate, so-- dium' biborate and potassium oh'lorid,'passing through the solution carbon dioxid to form and precipitate sodium bicarbonate,

then mixingr-the-solu'tion with a more or less soluble compound of an alkalineearth metal\ "to precipitate therefrom the correspondingbiborate, and-then recovering the :potassium chlorid-by ordinary evaporation.

'3 The 'method "of separately recovering saline substances from a solution containing "sod um carbonate, S0dl1lI1'l ,biborate, potassium chlorid, sodium. sulfateand sodium chlorid, which consistsin subjecting the solution (1) to evaporation at a temperature peratu're to not below "18 C. for separation of a mixture of sodium carbonate, sodium said three saltwmixtiire, (6)

dioxidthrough the greater than 33 C. for separationof sodium' chlo'ri'd'and sodium sulfate, and the so evap orated solution (2)-'to a. lowering "of tembiborate and potassium chlorid, (3') mixing the residual solution with a freshsupply of I the original solution, (4) repeating said evaporation and lowering 'oftemperature,

in order to obtainadditi'onal' yields of sodium-chlorid and sodium sulfate by evaporation and of said three salt mixture by lowering of I temperature,

a passing carbon so'. formed solution for precipitation of sodium bicarbonate, (7 mixingjtheresidual solution with amore or (5) redis'solving metal for biborate, and (8) evaporating the then remaining solution for recovery of potassium chlorid.

4. vThe method of separately recovering saline substancesfrom a solution containing sodium carbonate, sodium biborate, potasoration at a higher temperature-for separa- 7 tion of sodium chlorid, and the so evaporated solution (2) to a lowering of temper-' 'ature for separation of a mixture of sodium carbonate, sodiunrbiborate and potassium chlorid, (3) mixing the residual solution with a fresh supply of the original solution, (4 -repeating said evaporation and lowering of temperature in order to obtain additional yields of sodium chlo-rid by evaporationand of said three salt mixture by low lering of temperature (5) r'edissolving said three salt mixture,- 6) passing carbon dioxid through the sc -formed solution for method consists in.(1) subjecting such a so-' lut on who'se salts in partdecrease and .in

iquor with lowering of temperature and include sodium biboratein addition'to pota'ssium chloridto a cooling of the solution lowered in order to separate a mixture of salts which include sodium biborate. and. potassiu'm chlorid, (2) redissolvingsulting solution with a more or less soluble compound of an ,alkaline earth metal in order to obtain the boric acid of said sosalt. Y

6. Thehmethod of separately recovering saline substances from a solution con'tainin crease .in solubility in the mother liquor with loweringiof temperaturevand include bothsodium carbonate and sodium rbiborate in addition to potassium-chlorid to a cooling of' the solution saturated with all three of the last mentioned salts through a toms siumchlorid and sodium chlorid, which consists in subjecting the solution (1) to evapprecipitation of sodium bicarbonate, (7)

sodium and potassium salts, which metho consists :m (1) sutnectmg such a solution whosesa lts in part decrease and in part in- -less,soluble compound of an alkaline earth precipitation of the corresponding ing sodium and potassium salts, which i ioo part-increase in' solubility in the mother saturated with sodium biborate and 'potassium chlorid through .a temperature inter: va l in which part of the original salts in- ;crease in solubility as the temperature is the .so I I separated mixture, and (3,) mixing the're dium bibora'te in an insoluble form in which .it isreadily separablefromthe potassium saline substances from a solution contain -1ng sodium and potassium salts, which lution with a more or less soluble compound saline substances from a solution containing chlorid while the sodium sulfate remains in dium carbonate in addition tobothsodium v to hold sodium sulfate in solution "decreases with decrease of temperature, (2) bringing perature interval in which part of the original salts increase in solubility as the temperature is lowered inorder' to separate a mixture of salts which include sodium 'carbonate, sodium biborate and potassium chlorid, (2) redissolving theso separated mixture, and subjecting the resulting solution to the action (3) of carbon dioxi-d in order to convert sodium carbonate into sodium bicarbonate and (4) of a more or less soluble compound of an alkaline earth metal in order to convert'the boric acid of the sodium biborate into a salt of the alkaline earth metal. v p

7. The method of separately recovering method consists in heating such a solution whose salts include both sodium| sulfate and sodium biborate" in addition to potassium chlorid to a temperature above 33 C. in .order to have said solution in a condition in which itscapacity to hold sodium sulfate in solution decreases with increase of temperature and increases'with decrease of temperature, (2) bringing said solution to saturation with both sodium biborate and potassium chlorid while said solution remains in the condition mentioned with respect to sodium sulfate, (3) lowering the temperaturev of the-solution to not below 18 C. in order to-separate a mixture of sodium biborate and potassium solution, (4) redissolving the so separated mixture, and mixing the resulting soof an alkaline earth metal in order to obtain the boric acid of said sodium bibora'te in an insoluble form in which it. is readilyseparable from the potassium salt.

8. The method of separately recovering sodium andpotassium salts, which metho consists in (l) heating such a solution whose salts include both sodium'sulfate and so-- biborate and potassium =,chlorid "to a temperature above 33 C. in orderto have said solution in a condition in which its capacity with increase of temperature and increases said solution to saturation with sodium carbonate as well as wit-h both sodium biborate' and potassium chlorid while said solution remains in the condition'mentioned with respect to sodium sulfate, (3) lowering the temperature of the solution to not below -18 C. in order to separate a mixture of sodium carbonate, sodium biborate and potassium chlorid while the sodium sulfate remains in solution, (4 .redissolvin'g the so separated mixture, and subjecting the resulting solution to the action (5) of carbon diq'xid in order to convert sodium carbonate into so-- I dium bicarbonate, and (6) of a more or less; soluble compound of an alkaline earth metal in order to convert the boric acid of the .so-

dium biborate into, a salt of said alkaline 'earth metal. A 9. The method of. separately recovering saline substances from a solution containin sodium'andpotassium salts, which metho consists in (1) heating such a solution whose salts; includeboth sodium sulfate and sodium biborate to a temperature above-33 C. in order tohave said solution ina condition in which its capacity tofhold sodium sulfate in solution decreases with increase of temperature and increases with decrease of temperature, (2) bringing said solution to saturation withsodiumbiborate while said solution remains in the condition mentioned with respect to sodium sulfate, and (3) lowerin the temperature tonot below 18 C. in or er to separate sodium biborate while the sodium sulfatejremain's in solution. -10, The method of separately recovering saline substances from a solution containing sodium and potassium salts, which metho consists in (l) heating such a solution whose salts include both. sodium sulfate and so- 5 dium carbonate to -a temperature above 33. C. in order to have said solution in a condition in which its capacity to holdsodiumf sulfate in solution decreaseswith increase of temperature andincrea's es with decrease of temperature, (2) bringing said solution to. saturation with-sodium carbonate while said solution remains in the condition mentioned with respect to sodium sulfate, and} (3) lowering the temperature of the SOllltlQIl to notbelow 18? ,G .-"in orderjtoseparate so-- dium carbonate while} thesod-ium sulfate remains in solutionif" I In testimony whereof I have hereunto set my handin "the. presence of two subscribing witnesses. I r v CLINTON DOLBEAR.-, .Witnes'ses:

Faenors M. -WR IGHT,' D. B. RIonARns.-. 

